Solenoid assemblies are typically found in a myriad of modern products, from the control of anti-lock braking systems and automatic transmissions in automobiles, to pressurized water control in irrigation systems, to more general uses such as in doors, windows, many hydraulic controls, and the like.
Solenoids typically make use of a high magnetic reluctance region to facilitate movement of an armature along a set path in response to the application of an electric current. This region can be referred to as an “air gap” because empty space is commonly used as the high magnetic reluctance region. Such an arrangement with a literal air gap, however, may lead to certain difficulties in both construction and operation of the solenoid. Certain prior art teachings disclose the air gap may be achieved through a two piece construction of the solenoid with a gap left between the two pieces. Each piece may have a different conformation, meaning that separate, specialized manufacturing processes could be required for each piece. Further, if the two pieces need to be aligned properly to allow for easy movement of the armature through each piece and across the air gap, extra calibration and alignment procedures may be necessary. All of these additional steps generally increase manufacturing complexity, meaning more time and cost may be necessary to produce a single solenoid than if said extra calibration and alignment procedures were eliminated.
There may be the fear of decreased manufacturing efficiency and operational lifetimes associated with these prior art solenoids as well. For example, if a solenoid were produced in a two-piece arrangement with a certain degree of allowed deviation from the ideal alignment of the first and second piece, solenoids may be produced outside of this tolerance, and the time and cost necessary to produce said solenoid would have been wasted. Further, since a two-part construction like the one described above may be unlikely to produce ideal alignments on a consistent basis, the average operation lifetimes of the solenoids may decrease by general wear and tear (caused by frictional forces of the armature on the solenoid housing after days, months, or years of repeated rubbing due to misaligned solenoid components).
Further, traditional solenoid housing manufacturing and assembly is typically a multi-stage machining and welding process requiring a series of highly specialized machines, skilled manufacturing personnel, and time to perform each manufacturing step to produce a quality, reliable product. For example, the lathes which can be used for machining a central armature path in prior art processes are often expensive and require a large amount of space for proper operation, and welding methods may need to be completed in tight spaces and with little room for error or inconsistency in the weld. The imprecision and complexity of the prior art processes may produce solenoids and solenoid housings with inherent structural weaknesses, and produce them at a disadvantageously high rate. These manufacturing deficiencies may lead to premature operational failure of the prior art solenoid housings or a high rejection rate during the assembly process.
What is desired, therefore, is a method of making a solenoid housing which eliminates much of the manufacturing complexity found in the prior art. It is further desired that this novel method of making a solenoid housing improve the operation and increase the expectant operational lifetime of said solenoid housing.